1. Field of the Invention
The present invention relates to a package structure. More particularly, the invention relates to a package structure of a liquid lens.
2. Description of the Prior Art
The liquid lens refers to a lens having an adjustable focal length. Generally, the liquid lens can be one lens apparatus employing the mechanism of electro-wetting or one lens apparatus employing the mechanism of interfacial dielectric forces.
Please refer to FIG. 1. FIG. 1 illustrates a cross-sectional view of a traditional electro-wetting type liquid lens 60 disclosed in TW. Patent No. 200706917 (also US Patent Pub. No. 2007/0002455). As shown in FIG. 1, the liquid lens 60 has an expansion chamber 70 on its side, and the expansion chamber 70 is connected with a channel 74 to receive the overflowing liquid caused from the thermal expansion of the filled liquid chamber 61 inside the liquid lens 60. However, the expansion chamber 70 set aside will affect the optical design and the overall package assembly of the liquid lens unit; hence, it requires to be improved. Furthermore, being restricted to the operational principle of the electro-wetting type liquid lens, the package casing of the liquid lens 60 in FIG. 1 needs to be made of metal or electrically conducting materials, and thus the choice of the casing material is limited.
In addition, because each of the coefficients of thermal expansion for both lens liquids is larger than the casing materials, certain conventional package structure for traditional liquid lenses still exhibit the problem of liquid leakage when stored or operated under variations of environmental temperature.
Therefore, to solve the aforementioned problem, the main scope of the invention is to provide a package structure for a liquid lens.